Effects of acute water intake on body composition measurements by bioelectric impedance analysis

Abstract

Bioelectrical impedance analysis (BIA) is a simple and quickly applied non-invasive method used to assess body composition in clinical medicine and also sports science fort making important decision. BIA measurement is based on variance of tissue resistance to applied electric stimulation. Thus, changed of body water levels could have an impact on BIA measurements. We aimed to evaluate the impact of acute water consumption on body composition measurements using BIA in healthy females. A total of 50 subjects (mean +/- SD age: 21.8 +/- 1.6 years) were voluntarily participated to this study. Body composition was measured by foot to foot BIA before and 15 minutes after drank 1 litter of water. The percent of body fat mass (21.59 +/- 5.3 to 22.24 +/- 5.2, p<0.05) and fat mass (12.6 +/- 4.6 kg to 13.05 +/- 4.6, p<0.05) increased significantly after water intake compared to baseline value. Fat free mass (44.44 +/- 4.2 kg to 44.46 +/- 4.2, p=0.6) and total body water (31.82 +/- 3.2 kg to 31.83 +/- 3.3 kg, p=0.8) did not changed increased significantly (p=0.6) after water intakes. We show that water intake causes overestimate fat mass and percentage of body fat without any significant changes in body water levels and fat free mass values. Thus, investigator or clinicians should be considering low sensitivity of BIA application in patients or subjects with increased water levels especially under condition of existence of oedema.